Mix-in structure for gas or the like in pressurization centrifugal pump

ABSTRACT

A mix-in structure for a gas or the like in a pressurization centrifugal pump, capable of mix-discharging liquid and gas or the like to prevent cavitation and of suppressing gas residence in the pump chamber at the time of operation stoppage or the like. It comprises a drum-like case ( 4 ) having a suction port ( 2 ) and a delivery port ( 3 ), in which opposedly disposed are a vane wheel ( 5 ) radially formed with a plurality of vanes ( 19 ), a pressurization surface ( 36 ) formed with a compression chamber ( 33 ) opposed to the vane wheel ( 5 ) and converging from the suction port ( 2 ) toward the vanes ( 19 ), and pressurization section ( 16 ) formed with a pressurization partition wall ( 35 ) disposed close to the side surfaces of the vanes ( 19 ) to prevent leakage of the fluid in the vane chamber ( 27 ), wherein a gas supply device ( 6 ) is installed for supplying a gas into the suction port ( 2 ) by an increase in the liquid pressure in the delivery port ( 3 ) by using a pressurization centrifugal pump for pressurizing the liquid taken in from the suction port ( 2 ) in a pump chamber ( 9 ) defined by the vane wheel ( 5 ) and the pressurization section ( 16 ) and delivering it through the delivery port ( 3 ).

FIELD OF APPLICATION

The invention relates to a centrifugal compressor pump wherein animpeller wheel draws in gas and liquid through an intake duct and expelssaid gas and liquid through a discharge duct.

PRIOR ART

(1)

Centrifugal pumps that draw in and discharge air, water, oils and thelike draw in and discharge fluids only through the accelerated rotationof an impeller wheel in a case, thus making it difficult to increase thepressure of the discharge fluid in respect to the flow volume. Theapplicant has disclosed an improved type of centrifugal pressurizationpump in Japanese Patent Publication (Kokai) No. 2002-89477.

(2)

The centrifugal pressurization pump disclosed in this patent publicationincludes a drum-shaped case containing an intake port and a dischargeport, an impeller wheel formed of multiple radially disposed impellervanes, a pressure face forming a narrowing compression chamber extendingfrom the intake port and facing the impeller wheel, and a pressure blockforming a separation wall that stops leakage of the fluid in theimpeller chamber in the vicinity of the impeller vanes. The fluidentering from the intake port is compressed within the pump chamberformed by the impeller wheel and pressure block, and expelled from thedischarge port.

(3)

The above-described prior art centrifugal pressurization pump draws inwater from the intake port, infuses the air into the water underpressure within the pump chamber, and discharges the air-infused fluid(a mixture of air and water) from the discharge port. For example, whenused to wash fishing nets soiled with dirt or stubbornly adheredsubstances, this centrifugal pressurization pump exhibits theshortcomings of not being able to uniformly mix the air and liquidcomponents due to the large bubbles of air infused into the liquid, andalso due to easily generated cavitation.

(4)

Also, when the centrifugal pressurization pump described by theaforesaid patent attempts to infuse air into the fluid, small airbubbles mix into the fluid in the pump chamber through agitation.Although this can provide a more efficient washing action and anincrease in the volume of dissolved oxygen, noise is generated by theaction of the air moving around the pump chamber during the compressionprocess.

(5)

Therefore, regardless of the type of pump, and excluding otherrestrictions to the discharge duct system such as the connection of ahose and nozzle to the discharge duct, changes in the state of thepressurized fluid, induced by speed fluctuations of the impeller wheelfrom running start until stop, result in errors in the timing and amountof air supplied to the fluid, thus adversely affecting the dischargeperformance of the air-fluid mixture and making control difficult.

(6)

DISCLOSURE OF THE INVENTION

The present invention resolves the aforesaid shortcomings through a gasinfusion structure for a centrifugal pressurization pump that operatesby drawing in fluid from intake port 2, compressing the fluid withinpump chamber 9 defined by impeller wheel 5 and pressure block 16, andexpelling the fluid from discharge port 3. The centrifugalpressurization pump includes impeller wheel 5 formed of multipleradially disposed impeller vanes 19, impeller wheel 5 being installedwithin drum-shaped case 4 within which intake port 2 and discharge port3 are provided; pressure face 36 formed by narrowing compression chamber33 which extends from intake port 2 which opposes impeller wheel 5, andwhich faces impeller vanes 19; and pressure separator wall 35, formed onpressure block 16, which prevents leakage of fluid from impeller chamber27 from the side adjacent to impeller vanes 19.

The centrifugal pressurization pump is firstly characterized by gasinfusion unit 6 which supplies gas to intake port 2 based on an increasein fluid pressure at the aforesaid discharge port 3.

The centrifugal pressurization pump is secondly characterized byconstricting device 70 which is installed to discharge duct 20 which inturn connects to discharge port 3, the purpose of constricting device 70being to increase the fluid pressure in pump chamber 9.

The centrifugal pressurization pump is thirdly characterized by reliefvalve 75 which is installed to discharge duct 20, the purpose of reliefvalve 75 being to prevent the fluid pressure in pump chamber 9 fromexceeding a specified value.

The centrifugal pressurization pump is fourthly characterized bypressure differential ridge 39 which is formed on compression face 36between intake port 2 and pressure separator wall 35, and which providesa steeply inclined surface that induces a sudden change in flowdirection of the fluid and gas toward impeller vanes 19.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view of a centrifugal pressurization pump into whichthe gas infusion structure described by the invention is incorporated.

FIG. 2 is a partial cross section of the left side of the pump chamberof the FIG. 1 pump.

FIG. 3 is a cross section of the pump chamber of the FIG. 1 pump.

FIG. 4 is a perspective view of the structure of the case of the FIG. 1pump.

FIG. 5 is a cross sectional view illustrating the operation of the pumpchamber.

FIG. 6 is a cross section of the intake supply valve of the gas supplydevice.

FIG. 7 is a cross section showing the structure of the relief valve.

FIG. 8 provides three cross sectional views of the working part of thecompression chamber. The A, B, and C views are taken from lines A-A,B-B, and C-C respectively in FIG. 4.

FIG. 9 is a plan view of an additional embodiment of the centrifugalpressurization pump and gas infusion structure.

FIG. 10 is perspective view of the case structure of the FIG. 9 pump.

(7)

The following will describe embodiments of the present invention withreference to the drawings. Referring to FIGS. 1 through 4, pump 1 is acentrifugal pressurization pump equipped with the gas infusion structuredescribed by the invention. Pump 1 includes drum-shaped case 4 in whichare installed intake port 2 and discharge port 3, impeller wheel 5rotatably supported within case 4, and gas infusion unit 6 whichsupplies a gas, such as air and the like, to the internal region of case4.

(8)

In pump 1, impeller wheel 5 is driven by a motor attached to one side ofpump shaft 7 in the direction indicated by the arrow in FIG. 2. A liquidsuch as water, oil or the like, or a gas such as air and the like, or agas or liquid into which a medicinal substance or powder has beeninfused, is drawn into pump chamber 9 of case 4 through intake port 2,agitated and pressurized while the gaseous component is mixed into theliquid component, and expelled from discharge port 3.

(9)

The following will provide a detailed description of the structure andits operation. Moreover, this embodiment will be described using wateras the liquid and air as the infusion gas.

(10)

Firstly, as shown in the drawings, case 4 is divided into a pair of leftand right cases in the form of pressure case 4 a which includes intakeport 2, and impeller wheel case 4 b which includes discharge port 3.Pump chamber 9 is formed as a sealed space by joining the aforesaidcases together with screws or other like fasteners at multiple locationswith O-ring seal 10 and abrasion-resistant seal 11 (to be describedlater) placed between the opposing mating surfaces.

(11)

Impeller wheel case 4 b is a one-piece structure comprising perimeterwall 17 which has a width equal to that of pressure block 16 of pressurecase 4 a (to be subsequently described) inserted therein, and impellerwheel 5 at the external circumference of disc-shaped sidewall 15.Perimeter wall 17 is formed to a width and depth corresponding to thewidth and depth of multiple impeller vanes 19 of impeller wheel 5 whichis disposed at a specific location opposite discharge port 3. Dischargeduct 20 is a narrowing crescent-shaped channel that forms a singlestructure with discharge port 3.

(12)

Moreover, support brackets 21 and 22 connect to form a single structuresupporting pump shaft 7 at the external side of sidewall 15. Bracket 22supports the left and right-side bearings 23 of pump shaft 7 which islocated at the center of pump chamber 9. Component 23 a is a sealingplate provided at the bearing 23 side of bracket 22. Components 23 b isa mechanical seal, and 24 is a drain hole.

(13)

Impeller wheel 5, which includes multiple impeller vanes 19 arranged ina concentric radial pattern thereon, is removably attached to the end ofpump shaft 7 within pump chamber 9 through fastener 25 which may be ascrew, nut, or like fastening device. Impeller plate 26 and impellervanes 19 maintain respective close proximity, through small gaps, tosidewall 15 and perimeter wall 17 respectively.

(14)

Impeller wheel 5, as shown in FIGS. 2 and 5, is a one-piece structurethat includes impeller vanes 19, impeller plate 26 formed as adisc-shaped impeller sidewall, if formed as a one-piece structure on oneside of boss 27 a which also serves as an attaching part to pump shaft7. Impeller vanes 19 extend in a radial pattern, at specific intervals,from boss 27 a and along impeller plate 26. Impeller chamber 27 isformed as each region between impeller blades 19 which encapsulate thefluid media.

(15)

Impeller vanes 19, which are arranged in a radial pattern on impellerwheel 5, are approximately straight surfaces rearwardly inclined towardthe upstream side of the rotating impeller wheel (hereafter referred toas the upstream side). A scooping angle is formed at pressure case 4 aby the edge of each impeller vane 19 being further extended than itsbase part toward the downstream side of the rotating impeller wheel(hereafter referred to as the downstream side).

(16)

This configuration allows the rotation of impeller wheel 5 to moreeasily draw in fluid from intake port 2, hold the rotating fluid withinimpeller chambers 27, and applies additional centrifugal force,generated by the rearwardly inclined impeller blades, while the fluidwithin each impeller chamber 27 is carried toward discharge port 3, thusincreasing the fluid output pressure in the radial direction andimproving pumping efficiency.

(17)

Moreover, with impeller wheel 5 installed within impeller wheel case 4b, boss 27 a and the ends of impeller vanes 19 are the approximate sameheight as the flat end surface of divider wall 29 and in close proximitythereto, divider wall 29 being formed around the center of pressure case4 a (which will be subsequently described). Anti-abrasion seal 11 isinstalled between the two components. Multiple thru-holes 26 a penetrateimpeller vane plate 26 at appropriate locations to allow the passage offluid from impeller chamber 27 to mechanical seal 23 b.

(18)

The following will describe pressure case 4 a with reference to FIGS. 3through 5 (note: FIG. 5 is an illustration showing the operatingrelationship between compression chamber 33 and impeller vanes 19 withdischarge duct 20 and guide 50 oriented at 90° to the pump shaft.Pressure case 4 a forms a single structure with case cover 31 on whichare formed intake duct 30 and pressure block 16. With pressure block 16placed within the opening of impeller wheel case 4 b in which impellerwheel 5 resides, case 4 is sealed by securing case cover 31 to perimeterwall 17 with fasteners 13.

(19)

Pump chamber (pressure chamber) 9 is thus structured to allow impellerwheel 5 to draw in a largely unimpeded flow of fluid from intake port 2,compress the fluid between pressure block 16 and impeller wheel 5, andexpel the fluid from discharge port 3.

(20)

In other words, as shown in FIG. 5, pump chamber 9 includes intakechamber 32 which connects to intake port 2 at the beginning of theupstream portion of chamber 9 and promotes fluid intake, and compressionchamber 33 which compresses the fluid at the end of the downstreamportion of chamber 9. Also, pressure divider wall 35, which separatesintake chamber 32 from compression chamber 33 and prevents leakage offluid from impeller chambers 27, is formed between the end ofcompression chamber 33 and the beginning of intake chamber 32, the flatsurface of pressure divider wall 35 being formed on the same plane asthat of divider wall 29.

(21)

Intake chamber 32, compression chamber 33, and pressure divider wall 35thus interconnect to form a continuous structure around divider wall 29around the edge face of boss 27 a of impeller wheel 5.

(22)

Compression face 36, which is formed on the inner face of pressure block16 in the region extending from intake port 2 to pressure divider wall35, is structured as an inclined surface (to be subsequently explained)extending in the rotational downstream direction of impeller wheel 5.Compression face 36 inclines gradually upward from intake chamber 32 inproximity to the edge faces of impeller vanes 19, thus creating anarrowing passage that forms compression chamber 33.

(23)

As a result of this structure, the fluid coming into pump chamber 9 fromintake port 2 is held within each impeller chamber 27 and increasinglypressurized in compression chamber 33 by multiple impeller vanes 19which accelerate and discharge the fluid in a radial direction.

(24)

Compression chamber 33 extends up to compression termination point 37which is located at the leading edge of pressure divider wall 35. Thefluid from intake chamber 32, which has been accelerated in therotational downstream direction, is directed along compression face 36within impeller chamber 27, pressurized within pump chamber 9 withoutsudden compressive friction or other impedance, and expelled fromdischarge port 3 as pressurized fluid.

(25)

As shown in FIGS. 2, 4 and 5, pressure differential ridge 39 is formedon compression face 36, at a location along divider wall 35 after intakeport 2, as an inclined step-like surface that suddenly narrows the paththrough which impeller vanes 19 direct the fluid and gas. Secondcompression face 36 a, which is a narrowing wedge shape in crosssection, is formed between pressure differential ridge 39 and pressuredivider wall 36.

(26)

Pressure differential ridge 39, which is located at the leading edge ofdischarge port 3 on the upstream side of compression termination point37, accelerates the flow of fluid during its passage through compressionchamber 33, and as a result of its location at discharge port 3 in pumpchamber 9, has the effect of preventing a drop in fluid pressure whichwould otherwise occur during fluid discharge. This structure also hasthe effect of smoothly pressurizing and discharging the air supplied bygas infusion unit 6, and of suppressing noise and cavitation which canresult from infused air.

(27)

In other words, pressure differential ridge 39 extends outward fromdivider wall 29 in the radial direction in respect to compression face36, and inclines downward in the rearward direction upstream from therotating impeller wheel.

(28)

Moreover, as shown in FIG. 5, pressure differential ridge 39 may extendoutward from divider wall 29 as an inclined flat surface or smoothlyradius surface, when viewed in radial cross section, facing therotational downstream side. Formed as an inclined surface that risesfrom compression face 36 toward the outwardly facing edges of impellervanes 19, pressure differential ridge 39 provides a smooth transitionbetween pressure face 36 and 2^(nd) pressure face 36 a.

(29)

As a result of this structure, the fluid entering from intake port 2 ispressurized along a spiral path within impeller chambers 27, and thebubbles created by the infusion of air are reduced to an extremely smallsize while the fluid is driven in a circular path by impeller vanes 19,through narrowing compression chamber 33, while being increasinglypressurized against pressure face 36.

(30)

Therefore, due to the presence of pressure differential ridge 39, thefluid and air bubbles flow smoothly along pressure face 36 without beingsubjected to frictional shocks, thus the direction of flow is smoothlyaltered and directed toward impeller vanes 19 into impeller chambers 27.

(31)

Therefore, the air bubbles flowing toward compression termination point37 along pressure face 36 are quickly forced into impeller vane chambers27 after having been reduced to smaller bubbles by mixing into the flowwhere it separates from pressure face 36. From here the flow movestoward discharge port 3 from 2^(nd) compression face 36 a whichgradually approaches impeller vanes 19. The result is that noise issuppressed by the large amount of air bubbles that have entered thespaces between the edges of impeller vanes 19 and pressure divider wall35 after compression termination point 37. Furthermore, wear on impellerblades 19, which is normally caused by the air bubbles rupturing, isprevented.

(32)

Moreover, as shown in FIG. 5, it is preferable that pressuredifferential ridge 39 be located opposite discharge port 3 on theupstream side for the efficient discharge of air bubbles.

(33)

Furthermore, because the air supplied by gas infusion unit 6 does notremain within pump chamber 9 for an extended period of time, but isexpelled from discharge port 3 at each revolution, the air infusion anddischarge action within pump 1 is improved and cavitation prevented.

(34)

The following will describe pressure divider wall 35. The rearwardportion of pressure divider wall 35 includes pressure divider wallextension 35 a which is formed as a thinly extended part of pressuredivider wall 35 in proximity to impeller vanes 19. As shown in FIGS. 2and 5, pressure divider wall extension 35 a is located at the entranceto intake chamber 32, and when viewed from the side, appears a graduallynarrowing pointed portion extending over intake port 2, the underside ofpressure divider wall extension 35 a forming a narrowing smoothlyradiused opening that serves as an intake flow directing surface at theentrance to intake chamber 32.

(35)

This structure increases the surface area of pressure divider wall 35 asmuch as possible without shortening the length of the wall on thepressure chamber 33 side, and thus adequately maintains fluid pressureand increases intake efficiency.

(36)

Also, the surface opposing the aforesaid intake flow guide surface atthe beginning of compression face 36 is formed as intake guide face 36 bwhich is somewhat more acutely inclined than the inclined surface on thedownstream side, thus increasing efficiency by reducing resistance toand aiding the initial intake of fluid on the rotational downstream sideof impeller wheel 5.

(37)

Furthermore, fluid intake volume is enhanced and intake resistancereduced by forming intake port 2 as an oval shape with the long axisaligned along the rotating direction of impeller wheel 5 as shown inFIG. 2.

(38)

Because the fluid is increasingly compressed in a direction toward theradially inner portions of impeller chambers 27, which are formed asradial cavities defined by rearwardly inclined impeller vanes 19 inmutual juxtaposition, load shocks applied by the fluid against impellerwheel 5 are suppressed due to the fluid not being suddenly pressurized,and the pressurization of all the fluid within impeller chamber 27 ispromoted and maintained, thereby expelling the fluid at discharge port 3at maximum fluid pressure, and thereby expelling a large volume of fluidwith greater force and centrifugal extraction.

(39)

Moreover, compression chamber 33 is formed as a continuation ofplanar-shaped pressure divider wall 35 opposing multiple impellerchambers 27, and because pressure divider wall 35 prevents leakage ofthe fluid held within multiple impeller chambers 27 at the region wherecompression terminates, the pressure in compression chamber 33 ismaintained and thus assures a strong discharge of fluid. Pressurechamber 33 is shown in cross section in FIG. 8 for reference purposes.

(40)

The following will describe discharge port 3 of impeller wheel case 4 b.Discharge port 3 is located at the end of compression chamber 33. Inother words, discharge port 3 is formed as an elongated opening inperimeter wall 17 of impeller wheel case 4 b opposite to pressuredifferential ridge 39, 2^(nd) pressure face 36 a, and pressure dividerwall 35.

(41)

Guide vane 50 is formed within discharge port 3 in the lengthwisedirection in order to direct the exiting fluid. Pressure block 16 isstructured to reduce flow resistance and provide maximum pumpperformance in respect to fluid type, the number of impeller vanes 19,and other factors. For example, structuring pressure block 16 as acrescent shape has the effect of smoothly and gradually directing fluidflow downstream in a coherent state while preventing upstreamturbulence. The exiting fluid is directed to an external device bydischarge duct 20 which can be removably attached to the external sideof perimeter wall 17.

(42)

The following will describe gas infusion unit 6 with reference to FIG. 3and 6. As shown in FIG. 6, gas infusion unit 6 comprises intake infusionvalve 51 of which injection chamber 52 connects to intake duct 30through infusion duct 53, and infusion control chamber 55 that connectsto discharge duct 20 through control duct 56.

(43)

Infusion control chamber 55 and infusion chamber 52 are installed withinvalve body 57 and vertically separated by chamber wall 59.

(44)

Valve 62, which is installed so as to move along the vertical axiswithin infusion control chamber 55, is formed as a single structure thatincludes disc-shaped piston 60 and pintle valve 61.

(45)

Infusion control chamber 55 includes secondary infusion control chamber55 a located above piston 60 which connects to the external atmospherethrough vent duct 63, and internally installed spring 65 that appliespressures to valve 65.

(46)

In regard to the structure of infusion chamber 52, feed duct (gas supplyport) 66 leads from an external device to infusion chamber 52, and valve62, the lower end at which pintle valve 61 is formed as the valveoperating part, is slidably installed through the center of chamber wall59, thus allowing pintle valve 61 to open or block the port leading tothru-hole (valve orifice) 63 formed in infusion duct 53.

(47)

Intake infusion valve 51 operates by directing the pressurized fluidoutput from discharge port 3 to infusion control chamber 55 throughcontrol duct 56, thus raising valve 62 when the output pressure rises toa level that exceeds the predetermined control pressure applied topiston 60 by spring 65. The upward movement of valve 61 opens infusionduct 53 to allow the gas (air) supplied to infusion chamber 52 from feedduct 66 to be drawn into the fluid in intake port 2 (FIG. 5).

(48)

Also, when the fluid pressure within infusion control chamber 55 fallsbelow the predetermined spring pressure, valve 62 returns to a closedposition due to atmospheric pressure being applied to spring pressure.Therefore, gas is not injected when the pump is operating with low fluidpressure in pump chamber 9, a condition which can result, for example,from the reduced flow volume during pump start-up or from a blockage inthe intake system. Therefore, the termination of gas infusion at thistime hastens the buildup of fluid pressure in the pump.

(49)

Furthermore, because gas infusion automatically stops due to the drop influid pressure when pump 1 stops running, damage is prevented whichwould otherwise occur as a result of starting pump 1 with residual gasremaining in the pump.

(50)

Moreover, as shown in FIGS. 2 and 3, constricting device 70, which isinstalled in discharge port 20 on the downstream side of fluid pressuredetection orifice 67 which joins to control duct 56, generates aninitial outflow resistance within discharge duct 20 that, especiallywhen the pump is first turned on, makes it possible for fluid pressureto build up quickly within pump chamber 9.

(51)

In other words, the structural example of restrictor 70 described in thedrawings is formed as a ring-shaped member that extends inward from theinternal perimeter of discharge duct 20, the extent to which itprotrudes into discharge duct 20 can be altered by operating adjustmentscrew 71 of discharge pressure adjusting device 72.

(52)

If constricting device 70 protrudes a large amount, it significantlyrestricts the flow through discharge duct 20, thereby allowing fluidpressure within pump chamber 9 to build-up quickly when impeller wheel 5begins rotating at pump start-up. The fluid pressure is conveyed toinfusion control chamber 55 through fluid pressure detection orifice 67and control duct 56, thereby increasing the pressure within infusioncontrol chamber 55 to the extent where valve 62 rises to open valveorifice 63, thus allowing air from an external device to be injectedinto intake duct 30 through feed duct 66, infusion chamber 52, and valveorifice 63.

(53)

Disregarding conditions in which the outflow system connected todischarge duct 20 includes a nozzle, hose, or the like, this structureallows pump 1 to provide highly stable output of gas-infused fluid,thereby increasing the performance of various types of washing andtreatment operations that use a gas-infused liquid.

(54)

Moreover, although the drawings describe constricting device 70 as beingstructured to allow its adjustable protrusion into discharge duct 20through the use of discharge pressure adjusting device 72, constrictingdevice 70 may be fixedly installed within discharge duct 20 to providepartial blockage of the passage therein.

(55)

Furthermore, relief valve 75 (shown FIG. 7) is installed to dischargeport 3 in order to prevent damage to the pump which could be caused byexcessive pressure within pump chamber 9.

(56)

To explain more fully, relief valve 75 includes sealed main valve body76, which can be opened to the external environment, and separator wall77 formed within main valve body 76. Two spaces are provided in the formof upper and lower pressure monitoring chambers 78, and thru-holes 80,which are formed within separator wall 77, connect the upper and lowerchambers.

(57)

Pressure monitoring chamber 78 connects to intake duct 30 through bypassduct 79 a which joins to exhaust duct 79. Disc-shaped piston 81 andvalve 83, the lower end of valve 83 being formed as pin-shaped pintlevalve 82, are able to move vertically to open normally sealed exhaustorifice 85 of exhaust duct 84 through the removal of pintle valve 82there from.

(58)

Spring 87 is installed within secondary pressure monitoring chamber 78 aso as to apply downward pressure against valve 83, and monitoringchamber 78 a is connected to the external environment through vent duct86. Relief valve 75 is removably installed through the connection ofexhaust duct 84 to installation orifice 20 a on discharge duct 20 whichconnects to discharge port 3.

(59)

Relief valve 75, thus structured, allows valve 83 to rise up and openexhaust orifice 85 when the pressure within pump chamber 9 rises to alevel exceeding the predetermined pressure applied by spring 87, thusallowing part of the fluid to flow into pressure monitoring chamber 78through thru-holes 80 and back into intake duct 30 through bypass duct79 a.

(60)

The operation of relief valve 75 prevents the buildup of fluid pressurebeyond a predetermined value, improves the air infusion operation, andprevents excessive loads from being applied to impeller wheel 5 in pumpchamber 9 as well as the seals and metal components. Moreover, shouldthe pressure within pump chamber 9 fall below a specific pressure,spring 87 once again moves valve 83 downward to seal pintle valve 82against exhaust orifice 85, thus allowing pump 1 to operate normally ina stable running condition.

(61)

Furthermore, in cases where an excessive load has been applied to thehose system connected to discharge port 3, or where constrictor device70 has been erroneously operated, relief valve 75 will prevent damage tothe hoses and impeller wheel 5.

(62)

The following will describe the operation and application of pump 1 andits operation therein. The rotation of impeller wheel 5, which is drivenby a power source, results in impeller vanes 19 drawing in fluid fromintake port 2 into impeller chambers 27 which continually fill pumpchamber 9 with fluid moving in a rotational path.

(63)

The fluid is forced into and increasingly pressurized within impellerchambers 27 while moving along pressure face 36 in compression chamber33, and when reaching divider wall 35, is expelled through dischargeport 3 at an extremely high pressure generated by the shape of pressureface 36 and rotation of impeller vanes 19 that apply discharge pressureand centrifugal force to the fluid.

(64)

Pressure divider wall 35, which is formed at the end of compressionchamber 33, extends along multiple impeller chambers 27, and includespressure divider extension wall 35 a formed as an extending part ofpressure divider wall 35. Moreover, because discharge port 3, which islocated at the rotational upstream side of intake port 2, is formed asan elongated orifice extending over multiple impeller vanes 27, itbecomes possible to contain the fluid within multiple impeller chamber27 of impeller wheel 5 in a pressurized state, and at the same time toexpel the fluid from the elongated orifice of discharge port 3, thusresulting in a simple structure providing an increase in both fluid flowvolume and pressure.

(65)

Furthermore, impeller wheel 5 is formed as a single integrated structurecomprising impeller vanes 19, boss 27 a, and impeller plate 26 whereinimpeller vanes 19 are rearwardly inclined in a radial arrangement; theside and perimeter of each impeller vane chamber 27, which is formed asthe area between adjacent impeller vanes 19, is open; and discharge port3 is formed in perimeter wall 17 of impeller wheel case 4 b at alocation opposing impeller chambers 27. As a result of this structure,the fluid within pump chamber 9 is securely held within each impellerchamber 27, increasingly pressurized in the rotational direction, andsmoothly expelled from discharge port 3 due to centrifugal force.Moreover, as shown in FIG. 5, each impeller vane 19 is preferablystructured with its front surface, which faces the rotating direction,oriented so as to form a specific scooping angle, its base part formedto a thicker cross section than the tip part, and with a large radiusformed on the rear side of the base part in order to strengthen theimpeller vane and improve fluid discharge performance.

(66)

Because pump 1 is equipped with a gas infusion structure in the form ofgas infusion unit 6 that injects a gas into intake port 2 based on anincrease in fluid pressure from discharge port 3, an increase in thefluid discharge pressure at discharge port 3, resulting from theoperation of pump 1, will result in the automatic infusion of air andits mixing in with fluid at discharge port 3.¹ Therefore, a decrease influid pressure will cause gas infusion unit 6 to stop the infusion ofair, prevent a further drop in fluid pressure which would result fromair being injected when the pump is running with low fluid pressure inpump chamber 9, and suppress the entrance of residual gas within pumpchamber 9.

(67)

Due to pump 1 being equipped with discharge duct 20 and constrictingdevice 70 that increases the fluid pressure within pump chamber 9 (pumpchamber 9 comprising impeller wheel 5 and pressure block 16),constricting device 70 restricts the fluid exiting through dischargeduct 20, thus accelerating the rise in fluid pressure within pumpchamber 9 when the pump is initially operated (excluding the effect offlow resistance generated by a connected hose system), and thus promotesthe smooth mixing in of air supplied by gas infusion unit 6 during theinitial discharge of fluid.

(69)

Also, a drop in fluid pressure below a specific value causes reliefvalve 75 to close, thus promoting a smooth rise in fluid pressure duringthe normal operation of pump 1. Moreover, even if constricting device 70of gas infusion unit 6 were to be erroneously adjusted, damage toimpeller wheel 5 and other problems would be prevented because excessivefluid pressure is not allowed to build up in pump chamber 9.

(70)

Therefore, as a result of the air supplied to this type of pump 1structure mixing into increasingly pressurized fluid driven by impellervanes 19 across pressure face 36 within narrowing compression chamber33, fluid pressure and the spinning action break down the large airbubbles entering from intake port 2 into very small and uniformly sizedair bubbles that are mixed into the fluid and discharged therewith.Compared to a conventional air infusion type pump, the presentcentrifugal pressurization pump invention is able to provide a greatervolume of infused air and more stable operation.

(71)

Therefore, the invention is able to improve the performance of all typesof water-based cleaning processes such as water washing, aerating, andother operations.

(72)

Moreover, pump 1 includes pressure differential ridge 39, which isformed on pressure face 36 in the region between intake port 2 andpressure divider wall 35, in order to alter the direction of flow offluid and gas toward impeller vanes 19, and is thus able to guide thedownstream flow of fluid and air moving over compression face 36 intoimpeller chambers 27, and expel the media flow from discharge port 3without a decrease in pressure. This structure decreases noise andimproves pump efficiency by suppressing incoherent flow at the boundaryregion which would otherwise result from a large volume of air flowingbetween pressure divider wall 35 and impeller vanes 19.

(73)

Pump 1, with pressure differential ridge 39 being formed on compressionface 36, makes it possible to increase the air component to 30% or moreof fluid volume. Furthermore, when a large volume of air is mixed in bypump 1, a fluid comprising a liquid and very small bubble component maybe continually discharged, thus aiding in the operation of various typesof processes in which the pump is used.

(74)

While the operation of the embodied pump 1 equipped with the aforesaidair infusion device has been described with reference to air as theinfusion gas, the infusion gas is not limited to air, but may also takethe form of various types of gasses including gasses into whichparticulate matter has been mixed in as well as pharmaceutical,digestive, nutritional fluids and the like, thus making the pumpapplicable to a wide range of uses in various fields.

(75)

The following will describe an additional embodiment of the pump 1invention with reference to FIGS. 9 and 10. Descriptions of structuresand components essentially similar to those described in the previousembodiment have been omitted.

(76)

In this additional embodiment, pump 1 incorporates two interconnectedcompression chambers 33, two pressure blocks 16, two discharge ports 3,and two intake ports 2 oppositely disposed to impeller wheel 5 which issupported by a shaft in case 4 in a disposition similar to that of theprevious embodiment, thus providing a simple pump structure capable ofdrawing in and expelling a large volume of fluid through a singleimpeller wheel 5, and of injecting a gas into the flow of fluid throughgas infusion unit 6, and of discharging said fluid.

(77)

In other words, this embodiment of pump 1, as described in the drawings,incorporates two interconnected compression chambers 33, two intakeports 2, and two discharge ports 3, each pair of upper and lower intakeand right and left discharge ports being symmetrical disposed along theradial axis.

(78)

FIG. 9 illustrates pressure case 4 a to which two input ducts 30 aresymmetrically attached at upper and lower positions thereon, andpressure block 16 located opposite to and covering half of the radialarea of impeller wheel 5. Pressure block 16 includes a compressionchamber 33, an intake port 2, a compression face 36, a pressuredifferential ridge 39, a secondary compression face 26 a, and a pressuredivider wall 35. Furthermore, this illustration describes two intakeducts 30, each of which is connected to a respective intake port 2, andeach of which branches off from a common intake duct 30.

(79)

Impeller wheel case 4 b incorporates a pair of upper and lower dischargeports 3, each to which a discharge duct 20 is attached. Each dischargeport 3 is located opposite to a respective pressure differential ridge39 formed on each of the two pressure blocks 16. The discharge duct 20connecting to the opening of one discharge port 3 extends around in thedischarge direction to join to a discharge duct 20 connecting to theother discharge port 3.

(80)

With this structure, the liquid entering the two intake ports 2 flowsthrough symmetrically formed compression chambers 33 and pressure blocks16 and is discharged, under pressure, from each discharge port 3 in thesame manner as described for the previous embodiment.

(81)

By equipping pump 1 with a single impeller wheel 5 and multiplecompression chambers 33 and pressure blocks 16, each compression chamber33 being equipped with an intake port 2 and discharge port 3, pump 1 isa simple structure incorporating multiple pump chambers 9, and can thusbe manufactured at reduced cost.

(82)

In this embodiment of pump 1, intake duct 30 and discharge duct 20 arestructured similarly to their corresponding structures in the previousembodiment, and are similarly respectively equipped with intake infusionvalve 51 of gas infusion unit 6, relief valve 75, and constrictingdevice 70.

(83)

Therefore, this type of pump 1 structure allows the gas from gasinfusion unit 6 to be injected into intake duct 30 and mix in with thefluid in each pump chamber 9, thus allowing a large volume ofgas-infused fluid to be discharged from discharge ports 3.

(84)

Although this embodiment describes pump 1 as being equipped with twopump chambers 9, enlarging the diameter of impeller wheel 5 allows theuse of more than two pump chambers 9 while still maintaining the abilityto easily manufacture pump 1, and makes it possible to freely designeach pump chamber 9 to obtain desired performance characteristics.Moreover, intake duct 30 and discharge duct 20 can be independentlyattached to the intake port 2 and discharge port 3 of each pump chamber9, thereby allowing a single pump 1 to intake fluid from multiplelocations or discharge fluids to multiple locations.

Benefits Provided by the Invention

(85)

The following benefits are provided as a result of the above-describedgas infusion structure for a centrifugal pressurization pump.

(86)

Cavitation is prevented, the discharge of a highly gas-infused fluid isaided, and residual gas is prevented from remaining within the pumpchamber, when the pump is not running, as a result of the gas infusionunit supplying a gas or like substance to the pump chamber, through theintake port, based on fluid pressure at the discharge side of the pump,and as a result of the gas supply being stopped when fluid pressuredrops.

(87)

Moreover, the constricting device installed in the discharge ductprovides a simple method of restricting the outflow of fluid from thepump chamber, thus accelerating the build-up of fluid pressure in thepump chamber during initial operation of the pump, and therebycontrolling the infusion of gas from the infusion unit at initial fluiddischarge.

(88)

The relief valve installed to the discharge duct prevents a rise influid pressure in the pump chamber above a predetermined level, thuspermitting easier gar infusion while aiding in the prevention of damageto the impeller wheel, hoses, and other pump system components.

(89)

Furthermore, the gas and fluid are mixed and subsequently dischargedfrom the discharge port, without a drop in fluid pressure, due to thepressure differential ridge altering the flow of fluid and gas along thecompression face between the inlet port and pressure divider wall. Also,the supplied gas is discharged without continually rotating andremaining within the pump chamber.

1. A gas or like substance infusing structure for a centrifugalpressurization pump, comprising: a drum-shaped case in which an intakeport and a discharge port are formed, and to which is installed animpeller wheel including a plurality of radially disposed impellervanes; a compression face defining a narrowing compression chamberopposing the impeller vanes from the intake port side facing theimpeller wheel; and a pressure block on which is formed a pressuredivider wall that prevents the leakage of fluid from within impellerchambers formed between the sides of impeller vanes, wherein the fluidentering the centrifugal pressurization pump from the intake port ispressurized within a pump chamber formed by the impeller wheel andpressure block and discharged through the discharge port, and wherein agas infusion unit supplies a gas to the intake port based on increasedfluid pressure at the discharge port.
 2. The gas or like substanceinfusing structure for a centrifugal pressurization pump according toclaim 1, wherein a constricting device is provided within the dischargeduct which connects to the discharge port, said constricting deviceconfigured to increase the fluid pressure within the pump chamber. 3.The gas or like substance infusing structure for a centrifugalpressurization pump according to claim 1, wherein a relief valve isinstalled to the discharge duct to prevent fluid pressure within thepump chamber from rising above a predetermined level.
 4. The gas or likesubstance infusing structure for a centrifugal pressurization pumpaccording to claim 1, wherein a pressure differential ridge is formed onthe compression face that extends from the inlet port to the pressuredivider wall, said pressure differential ridge being formed as anacutely inclined partial surface that diverts the flow of fluid and gastoward the impeller vanes.
 5. The gas or like substance infusingstructure for a centrifugal pressurization pump according to claim 2,wherein a relief valve is installed to the discharge duct to preventfluid pressure within the pump chamber from rising above a predeterminedlevel.
 6. The gas or like substance infusing structure for a centrifugalpressurization pump according to claim 2, wherein a pressuredifferential ridge is formed on the compression face that extends fromthe inlet port to the pressure divider wall, said pressure differentialridge being formed as an acutely inclined partial surface that divertsthe flow of fluid and gas toward the impeller vanes.
 7. The gas or likesubstance infusing structure for a centrifugal pressurization pumpaccording to claim 3, wherein a pressure differential ridge is formed onthe compression face that extends from the inlet port to the pressuredivider wall, said pressure differential ridge being formed as anacutely inclined partial surface that diverts the flow of fluid and gastoward the impeller vanes.
 8. The gas or like substance infusingstructure for a centrifugal pressurization pump according to claim 5,wherein a pressure differential ridge is formed on the compression facethat extends from the inlet port to the pressure divider wall, saidpressure differential ridge being formed as an acutely inclined partialsurface that diverts the flow of fluid and gas toward the impellervanes.